Sabanci University Nanotechnology Research and Application Center, Orta Mah., 34956 Istanbul, Turkey.
Faculty of Engineering and Natural Science, Sabanci University, Orhanli, Tuzla, 34956 Istanbul, Turkey.
Biosens Bioelectron. 2017 May 15;91:225-231. doi: 10.1016/j.bios.2016.12.041. Epub 2016 Dec 16.
E. coli O157:H7 is an enterohemorrhagic bacteria responsible for serious foodborne outbreaks that causes diarrhoea, fever and vomiting in humans. Recent foodborne E. coli outbreaks has left a serious concern to public health. Therefore, there is an increasing demand for a simple, rapid and sensitive method for pathogen detection in contaminated foods. In this study, we developed a label-free electrical biosensor interfaced with graphene for sensitive detection of pathogenic bacteria. This biosensor was fabricated by interfacing graphene with interdigitated microelectrodes of capacitors that were biofunctionalized with E. coli O157:H7 specific antibodies for sensitive pathogenic bacteria detection. Here, graphene nanostructures on the sensor surface provided superior chemical properties such as high carrier mobility and biocompatibility with antibodies and bacteria. The sensors transduced the signal based on changes in dielectric properties (capacitance) through (i) polarization of captured cell-surface charges, (ii) cells' internal bioactivity, (iii) cell-wall's electronegativity or dipole moment and their relaxation and (iv) charge carrier mobility of graphene that modulated the electrical properties once the pathogenic E. coli O157:H7 captured on the sensor surface. Sensitive capacitance changes thus observed with graphene based capacitors were specific to E. coli O157:H7 strain with a sensitivity as low as 10-100 cells/ml. The proposed graphene based electrical biosensor provided advantages of speed, sensitivity, specificity and in-situ bacterial detection with no chemical mediators, represents a versatile approach for detection of a wide variety of other pathogens.
产志贺毒素大肠杆菌 O157:H7 是一种肠出血性细菌，可引起人类腹泻、发热和呕吐，是导致严重食源性疾病暴发的罪魁祸首。最近发生的食源性大肠杆菌暴发事件对公众健康造成了严重影响。因此，人们对用于污染食品中病原体检测的简单、快速和灵敏方法的需求日益增加。在本研究中，我们开发了一种无标记的电化学生物传感器，该传感器与石墨烯接口，用于灵敏检测致病菌。该生物传感器通过将石墨烯与互穿微电极的电容器接口来构建，该电容器通过大肠杆菌 O157:H7 特异性抗体进行生物功能化，用于灵敏的致病菌检测。在此，传感器表面上的石墨烯纳米结构提供了卓越的化学性质，例如高载流子迁移率和与抗体和细菌的生物相容性。传感器通过（i）捕获细胞表面电荷的极化、（ii）细胞内部的生物活性、（iii）细胞壁的电负性或偶极矩及其弛豫以及（iv）调节石墨烯的载流子迁移率来转换基于介电特性（电容）变化的信号，一旦致病性大肠杆菌 O157:H7 被捕获在传感器表面上，这些信号就会改变电特性。因此，基于石墨烯的电容器观察到的灵敏电容变化特异性地针对大肠杆菌 O157:H7 菌株，其灵敏度低至 10-100 个细胞/ml。所提出的基于石墨烯的电化学生物传感器具有速度快、灵敏度高、特异性和原位细菌检测等优点，无需化学介质，代表了一种用于检测各种其他病原体的通用方法。
